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The role of protective coatings in maintaining our wind turbines

With thousands spanning the landscape and clustered around our shoreline, wind turbines are an integral source of renewable energy for the UK. However, studies show that without adequate surface protection and maintenance, annual turbine output can fall by 20%.

Wind turbines are the largest renewable energy source in Europe, and so effective maintenance is essential.

The average wind turbine is expected to operate continuously for around 15 years but over that time the energy generated by the turbine can be severely impacted by wear and tear from the elements.

With an 80 m/s tip speed, a 2mm diameter rain droplet can impart 120MPA on a turbine blade – a figure that is in fact higher than the yield stress quoted by some turbine blade materials.

Such impacts lead to pitting, particularly on the leading edge of blades. This results in a fall in aerodynamic performance and a subsequent loss in blade efficiency – some studies have shown that leading edge erosion can cause a 500% increase in drag, resulting in a significant 20% fall in annual wind turbine energy output.

It is estimated that blades are responsible for 22% of wind turbine component failure and so many operators are investing in preventative maintenance to overcome the challenges posed by turbine component failure.

The challenge for offshore turbines is multiplied as the blades are typically larger and so rotate at a higher speed, resulting in higher velocity impacts from rainfall. The maintenance challenge presented in such environments also limits the options for in-situ repair.

The wind turbine repair and maintenance solution

Where turbine blades are concerned, it is important to specify the optimum coating solution before the part is assembled.

For turbine OEMs partnering with a surface engineering specialist helps outline not only the optimum coating but also the optimum application process. It is important to consider coating and application as very often the optimum coating can prove to be unworkable from an application perspective; too expensive; too long to apply; unsuitable for in-situ maintenance.

Aside from blade leading edge maintenance, the inner workings of wind turbines also need ongoing repair to ensure efficient operation.